Conventionally, a spark plug is used in an internal combustion engine. To reduce the radio wave noise generated by ignition, there is proposed a technique that arranges a resistor element between a center electrode and a terminal metal fitting.
Nowadays, further improvements in electrical noise performance and in durability are required due to a high-power engine or similar reason.
The main advantage of the present invention is to improve the suppression performance of the radio wave noise and the service life of the resistor element.